An Integral Part of the Equation
by JennyLD
Summary: He watches from the sidelines, unaware that he is important too. Tencest/Rose


**Disclaimer:** Doctor Who owns my soul, I own nothing.**  
Spoilers: **None  
**Summary: **He watches from the sidelines, unaware that he is important too. **  
Prompt: F**_rom voyeurism to participation  
_**Thanks To: **Sinecure for the beta**  
Author's Notes: **Written for Rynne for bidding on me during the April 2009 Support Stacie Author Auction.

Sucking in a ragged breath, the Doctor watched Rose shift on the bed. Twisting, writhing restlessly, she arched her back, body lifting off the rumpled sheets. Even from this distance, from the other side of her doorway, he saw the flush to her skin, saw the single bead of sweat slowly slip down her neck...

And, just for a moment, he imagined his tongue following its path. Slipping between well-rounded breasts, sliding across a smooth, well-muscled stomach, circling around her belly button, before finally reaching the juncture between creamy white thighs. But someone else had beaten him to it.

His hands clenched into fists at his sides, nails digging into his palms.

It should be _him_ there next to her, touching her, running his palm down her side, mapping out a hip and tickling the fine, downy-soft hairs already damp with desire.

It should be him kissing her. His lips pressed to her kneecap, his tongue darting out to taste her innermost folds. His teeth nipping at the tiny bundle of nerves that'd soon send her over the edge into oblivion. It should be him buried between her legs, brown hair--already tousled from a proper snogging--sticking wildly about. Him spreading her further, taking her deeper, pushing her faster. Him...

Being touched _by_ her.

It was one of his most frequented daydreams: her fingers tangled in his long strands, pulling him closer. Pressing his nose further into her scent, molding his mouth more firmly around her intimate flesh.

It was h_is_ fantasy. The dream that kept him going during the time they'd spent apart, separated by the unbreachable wall between universes. The image that he stroked himself to.

His utopia.

And seeing her touching another man like that, giving that attention to someone else was too much. Like the straw that broke the proverbial camel's back, only stronger, shattering all his outdated hang-ups, all of his people's self-imposed rules.

Pushing the bedroom door open, he strode across the room, determined to make Rose understand--to make them both understand that she was _his_.

No one else's.

"About bloody time," his duplicate moaned, lifting his gaze to the Doctor's. Familiar brown eyes danced confidently as he made a show of wiping his chin, and then slipped out from between Rose's legs, sliding off the bed. "Knew you were stubborn but that's gotta be a record, even for you. Me. Well...us."

The Doctor's eyes narrowed on his double, then flitted to Rose, lying there watching him, breath coming out in ragged bursts. Her hands clenched in the sheets and she squeezed her thighs together for friction, looking incredibly turned on.

And guilty.

The two of them had...planned this? Together? Well, that explained their recent closeness. The way they spent so much time together, talking in hushed voices, leaning conspiratorially over the kitchen table. He'd just figured it was the human connection they shared. Nothing more.

But the...overly loud, extremely energetic noises he'd heard from all the way down the hall in the console room? Walls as thick as steel, the TARDIS had, and the Doctor wondered if maybe she was in on it as well.

And the whole door standing wide-open thing? Who kept their bedroom door open when shagging, unless they either knew they wouldn't get caught or _wanted_ to?

There was only one reasonable explanation: they'd planned it all, every last detail.

Biting back a groan, he turned to leave, but found himself face-to-face with a very human, very naked him. "Nope." The man actually had the audacity to pop the p. "Didn't go through all that trouble just for you to turn tail and run. Stupid Time Lords rules."

The Doctor wanted to remind him that he used to be a Time Lord as well. Still was in a way. Had the mind of one anyway, even if he didn't have the two hearts or the get-out-of-death-free-by-regeneration card. He wanted to tell him that he wasn't all that different now, wasn't that far removed from the stupid rules he seemed so disgusted with. Rules that had kept their kind from interfering too much in the affairs of others, rules that had made him...them--

"The lonely God," the human him interrupted, not needing to be slightly psychic to know what he was thinking. They were the same after all. Looked the same, thought the same, _felt_ the same_._ "Never much liked that title myself. Didn't think you did either." His tone was more than a little accusatory and the Doctor shook his head.

"I'm no God," he insisted, turning back to Rose. To everything he'd ever wanted. Needed. Desired.

And never had the audacity to take.

She was watching them, eyes darting back and forth and worrying at her bottom lip--a nervous habit that had always caused him no end of frustration. Especially when she did it during dangerous situations, proving to be more than a little distracting. Nearly got them both killed--well, jailed...okay, so it _had_ gotten them jailed on more than one occasion. She didn't know that though.

Wasn't it was entirely his fault. It'd always been so hard not to imagine what those teeth would feel like nibbling on his lips, biting down on his neck. Scraping gently along his length.

And her lips! He groaned. Once his mind started on these fantasies, it was hard to stop. Hard not to think about her lips wrapped around him, surrounding him. Slurping, smacking, sucking...making other delectable noises deep in her throat.

They were right there within his reach. All he had to do was bend over ever so slightly and take them, press his mouth to them. Part them with his tongue. She wouldn't stop him. Neither would their audience of one.

_Watching_. The Doctor could feel his duplicate watching them. Him. Waiting. Wanting to see if he'd accept the chance he was being given and finally--_finally_--take what he'd always wanted.

Did want. So very badly.

Feeling a shiver run down his spine, he tried to quiet the moan that was rising up in his throat. Tried and failed. He closed his eyes, hoping they hadn't heard. Hoping also that neither of them noticed the bulge quickly growing in his trousers. He'd already been half-hard when he entered Rose's room, and now, standing so close to her, surrounded by her scent--vanilla and honey and _musk_--it didn't take much before he was straining against the cotton confinement of his pants.

Without thinking, he leaned down, bracing himself against the headboard. He tilted his head, adjusting hers at the same time with a hand in her hair, guiding her to him. Pressing cool lips to her warmer ones, softly, gently, just a quick peck to satisfy the need. Nip it in the bud before it got out of hand...

Like what? he thought with a mental snort. Had him barging into her room where she was naked, horny and ready? That kind of out of hand?

A breath escaped his lips and the spell was broken. He couldn't allow himself to get lost in Rose. Pulling back quickly, fully intending to stop things before they got even more out of hand than they already were, he ran right into a hard, unyielding body.

Warm, human breath tickled the hairs on the nape of his neck. "She wants you, Doctor. Always has. Always will. Just look at her."

Despite knowing it was a very bad idea--so bad, in fact, it topped the list of very bad ideas—he did as he was told. Gaze following a path similar to the one he'd followed in his mind's eye earlier, he took all of her in. Drank her up. Feasted on her. Her heavy-lidded gaze, her rosy, pebbled nipples, the way her chest rose and fell rapidly with each breath. He simply couldn't get enough. Could, in fact, stare at her like this all day and never tire of it. Never grow bored or antsy. Forget new planets and races he'd never encountered before; all the exploring he'd ever need could be found right here, in this bed.

"Touch her."

Drunk on Rose--the sight of her body, bared to him, her overwhelming scent tickling his nostrils--he didn't need to be told twice. Reaching out to cup her cheek, he ran his thumb softly over her lower lip. He could have that if he wanted it. Gaze slipping to her chest, he realized he could have that too. Further...and that could be his as well.

All he had to do was ask.

"Touch me, Doctor." Rose repeated his double's words, giving him the permission he needed. Eyes steady on him, she reached up and grabbed his tie, dragging him down to her slowly, hand-over-hand. Another of his fantasies come true and he couldn't help it.

He came undone.

Swinging a leg over her body, he quickly climbed up onto the bed, trainers and all, and hovered over her, just out of touching distance. She arched her back, seeking out his hardness, his touches, squirming restlessly, rubbing herself against him, straining for friction in all the right places. But he held himself away from her, kept himself at a distance, wanting to enjoy the moment just a little bit longer. Wanting to commit to memory the way she looked, lying beneath him. When his refusal lasted longer than her patience, she resorted to aggression, yanking on his tie, trying to pull him down closer...or to knock him off-balance, watch him topple on top of her. He wasn't sure which.

"Ah-ah," he said with a grin, then moved in, peppering kisses along her jaw, her neck, her chest. Trailing his hand down her body, he wasted no time in touching her in the exact spot he wanted to most. The exact spot she wanted him most as well. He felt her moisture on his fingertips and her sharp intake of breath on his lips.

"Please," she begged, hips bucking up, pressing his fingers deeper into her slick folds. "Please, I need you to...need you to--oh." Her eyes squeezed shut, the breath she'd just drawn in coming out in a harsh exhale as he dipped first one, and then a second finger into her sopping wet channel.

She was so ready for him that he slid right in, all the way up to his second knuckle, her velvety tightness causing a moan to bubble up in his throat. There was an answering groan from the foot of the bed, and, tearing his lips away from their slow ascent up the side of a breast, he threw a glance over his shoulder. Saw the human him there, at her feet.

Hard cock resting against her stomach.

He wrapped a hand around each of her ankles, gently caressing the skin of her calf, then slowly, ever so slowly, spread her legs apart. Opening her to his gaze.

Watching her.

A surge of jealousy rose up in the Doctor. Though he wasn't necessarily opposed to sharing--with himself...he was too possessive to let someone other than another incarnation of himself touch Rose--he wanted his double to know, in no uncertain terms, that she was his first.

Making a show of capturing her lips in a frantic kiss, of claiming her mouth, he continued to lightly tease between her legs. Her lips, already slightly parted, opened up more fully under his, and he ran the tip of his tongue along them, letting her flavor--mint from her toothpaste and strawberries from her breakfast--explode along his taste buds. Now that he was actually kissing her...actually, finally, thoroughly kissing Rose Tyler, he wanted to savor every second.

Her lips were warm, her tongue seemingly everywhere at once. First in his mouth, stroking along the inside, then retreating, back to her own mouth, waiting for him to follow. Releasing his tie, she ran her hands down his back and he could feel the bite of her nails even through his suit jacket. Fingers digging into his arse, grasping at it, she pressed him down, pushing into him at the same time.

The contact between her body and his throbbing erection was almost too much to bear and he fell forward, catching himself on his arms. Hips bucking, mimicking thrusting inside her, he moaned at the friction it created. Felt her echoing moan vibrate over her skin as he buried his face between her breasts...trying to catch his breath, to get a handle on his desire, which was quickly spiraling out of control.

"Fuck me," she demanded and his cock jumped at the sound of her wrapping her voice around that naughty word. At the thought of Rose Tyler talking dirty to him. "Want you to fuck me. Now--please, now." Her fingers were clenching in his suit jacket, tugging at it, fisting it in her hands.

Rolling off her, the Doctor swung his legs over the side of the bed, working quickly to get undressed. His trainers dropped to the floor with a thud but the sound barely registered. All he could hear was Rose; panting, breathing heavily, faster, with each passing moment, with each article of clothing he managed to tear off himself. Socks went next, then suit jacket and shirt were ripped open, sending buttons clattering everywhere. Standing up, losing that little bit of contact he still had with her body, required more strength than he thought he was capable of producing at the moment but he needed to be inside her, n_ow_.

Quickly fumbling with his button and zip he released both with a groan, feeling the pressure on his cock diminish just a bit. He dropped both trousers and pants at the same time and stepped out of them before turning to face Rose. Coolish-warm hands grasped him from behind, slowly slipping his jacket and shirt off his shoulders, letting them fall to a puddle on the floor.

The fact that his human counterpart was undressing him didn't shock him. Nor did the fact that he was touching him. The Doctor was 900 years old after all and there wasn't much he hadn't seen or experienced over the years.

Rose, however...Rose was, as Jack had liked to point out, from the twenty-first century. A time when morals were still a bit backwards and unusual sexual preferences were something to be ashamed of, hidden.

The Doctor watched as her eyes widened a bit and realized that this probably wasn't part of the original plan. Leaning over her, he traced a finger along her jaw, directing her gaze back to him. "So beautiful," he murmured.

She didn't look upset, just...slightly unsure of herself.

"Wanted you for so long," he continued, climbing back on to the bed next to her and dipping down to kiss the invisible line he'd just traced. "Wanted to touch you..." Sliding a hand down to cup a breast, he shifted over her. "To taste you..." He nipped at her bottom lip, settling more firmly between her legs, distracting her from the person climbing into bed with them.

Watching his duplicate adjust himself next to Rose, he felt a twinge of excitement. He knew that body so well. Knew it...well, like the back of his hand. Knew every dip and curve, every mole and imperfection. And its owner knew the Doctor's body as well. Knew what turned him on and what didn't. Knew where to touch him to make him grunt in pleasure.

He bit back a groan.

But this was about Rose. He wanted to make it amazing for her. Wanted to give her everything she wanted and more. Everything she deserved. And this--him, the other him...she obviously loved them both. Wanted them both. He'd seen it in her eyes these past few months, as they'd traveled together. Seen the way her brows would draw down in confusion when things were quiet and they were all in the same room together. She couldn't choose between them.

And he wouldn't ask her to.

Slipping slowly into Rose's folds, the head of his cock just barely breaching her center, he thumbed a nipple, feeling it harden under his touch. Her hands scrabbled on his back, trying to push him in further, to get him right where she wanted. Right where he wanted too. But there were other things to think about first.

"Rose." She could have them both if she wanted. "Rose, look at me." She didn't have to choose just one or the other. Not if she didn't want to.

Her eyes slowly slid partway open and he noted how dilated her pupils were. Gaze, lust-heavy and dark, darted from his face to his groin, and then back again. He was about to point out to her that they weren't alone when something caught her attention and she snapped her head to the side, eyes widening on the man laying next to her.

"This alright?" the human him asked quietly, reaching out tentatively to stroke her cheek.

She turned back to the Doctor, silently questioning him with her eyes.

"Your decision," he told her gently, refraining from giving an opinion on the matter. He didn't want to influence her decision. Didn't want her to say yes or no because of something he said. Or didn't say.

She could end up regretting it later.

"Y--yeah. I mean..." She flitted her gaze between the two of them, tongue peeking out from between her teeth, obviously mulling over the possibilities. "Is it all right with the two of you?"

Before he could answer, his double leaned in, whispering something in her ear, letting his hand trail down to cup a breast. Her eyes widened almost instantly, gaze flitting to the Doctor, and he knew it had nothing to do with the hand touching her.

And, at the same time, wasn't entirely sure he wanted to know what sorts of sordid tales she was being told.

Like that time on Asceilet Minor. The week-long orgy he'd attended there. He was younger then, more into experimentation and trying new things.

Now he was just into Rose.

But Rose was paying more attention to the other him right now and that just wouldn't do. Taking up post by her other ear, he positioned his cock at her entrance again and breathed out, "Gonna fuck you." Her gasp was instantaneous and he knew it was because of him this time, not his double. "That okay with you?"

Feeling her nod her head in agreement, the Doctor slowly slid into her warm depths. Inch by agonizing inch, exerting a control over himself that he was shocked he even had anymore. Snaking his arms beneath her, he grasped at her shoulders, settling himself as deeply inside her as he could, eyes squeezing shut at the perfect feel of her surrounding him.

"So tight," he moaned, pulling slowly back out of her, feeling her muscles clench around him, trying to stop his retreat.

Her hands clutched at his back, nails digging into his flesh as she arched up, pressing her breasts against his chest. She wrapped her legs around his waist and bucked up into him, holding him tightly to her trembling body.

She wasn't going to last long. Not at this rate. And certainly not after having his twin's mouth buried in her folds first.

And most definitely not during her first time with two men focusing all of their attention solely on her.

He lifted his head, to see what his double was doing and found him still attached to her ear, no doubt talking dirty to her, telling her all the things he--_they_--wanted to do to her. _Would_ do to her. Over and over again. All night long.

The Doctor didn't plan on any of them leaving this bed for a very long time. Not for days at least. There was so much to do, so much to explore and..._re_explore.

Thrusting back into Rose, he pulled his thoughts away from later and focused on the here and now. This time was about Rose. Next time it would be about the other human in the bed. And maybe the time after that about the both of them at once.

The Doctor grinned, pulling out and thrusting back in again, delighting in the way Rose squeezed him just so. He took a nipple into his mouth, scraping his teeth along it, then soothed it with his tongue. Sucking, licking, biting, knowing, _feeling_ his twin beside him, lavishing the same attention on her other breast.

He fucked her harder at the thought. Went deeper with each inward stroke, pulling nearly completely free on each outward one. The loss of her warmth and then suddenly being surrounded by it again had him on edge within minutes.

He drew his teeth over her nipple.

Her muscles clenched tighter on him.

Shifting above her, adjusting himself, angling just so...

"_Fuck_," she hissed, arching higher, and he knew he'd found it. He began thrusting faster, concentrating on that one spot inside her, reaching between their bodies to rub at her clit with his thumb.

"You're so wet, Rose." He popped her nipple out of his mouth, raising his head and watching as she tossed hers against the pillow, hair spread around her in a mess that forced a thrill down his spine. She was gasping for air, so close now. Just about there.

So was he.

His duplicate moved up her body, taking his turn at claiming her mouth in a bruising kiss. Instead of inciting jealousy in the Doctor though, it only fueled his desire. And when a warm human hand joined his in touching Rose, he felt his balls drawing up close to his body, felt the telltale tautening that meant he was about to come.

Slowing his thrusting down, he focused more on her clit and that sweet spot inside her. The spot that had her gasping each time he hit it. "Rose," he begged, wanting her to come first. Wanting to see to her needs, instead of his own selfish ones, but if she didn't hurry up, he'd lose all control. "Can't hold on."

"Rose," his duplicate whispered, pulling back to gaze at her and the Doctor knew that he wanted to watch her when she came. Knew because he wanted it too. "Come, Rose." His hand rubbed faster, brushing the Doctor's cock with each pass, and the Doctor knew it wasn't an accident.

And then--finally...

Hips thrusting up, riding him from below, Rose bucked wildly beneath him. Her hands fisted in the damp sheets and she threw her head back, mouth open, in a silent scream. Wave after wave, her orgasm flowed through her, causing her intimate muscles to clench down on his cock, grasping him so tightly that it took his breath away.

The Doctor sped up, slamming into her faster and faster. Deeper and deeper. Moaning low, in the back of his throat, he thrust into her with abandon, any sense of rhythm long forgotten about. Then he felt nimble fingers kneading his balls and recognizing the feel of them, knowing who they belonged to, he careened over the edge, falling forward as he came, stars bursting on the backs of his eyelids.

Wrapping Rose in his arms, he held tightly to her as his body rode out the last waves of pleasure. Despite his superior Time Lord physiology, he had to struggle to catch his breath, waiting as his heartbeats gradually slowed to a more normal rate.

Maybe he was getting old.

With a snort, he lifted his head, staring straight into the eyes of the woman he loved. And had just shagged. He, the Doctor, had just shagged Rose Tyler. And would probably do so again. Definitely would.

And often.

Leaning down, he pressed a kiss to her lips, losing himself in the feel of her warm mouth and soothing hands.

"Oi, you two," a familiar--as in back of his hand familiar--voice spoke up. "D'you mind helping out a bit here?"

Tearing their mouths from one another, the Doctor and Rose turned to stare at his twin, who was lying beside them, one hand clutched tightly around his straining erection.


End file.
